NIDCD Project Description: The AGES&#8722;Reykjavik Study is examining genetic susceptibility and gene/environment interaction as these contribute to phenotypes common in old age, including hearing loss. The NIDCD funding of the hearing component and balance questionnaires for this study will support audiometric examinations consisting of otoscopy, acoustic immittance (bilateral tympanometry and ipsilateral acoustic reflexes), and pure-tone, air-conduction audiometry to determine hearing thresholds in each ear at 500, 1000, 2000, 3000, 4000, 6000, and 8000 Hz. Through a prior IntraAgency Agreement with the National Institute on Aging (NIA), NIDCD funded hearing exams on about 5,200 subjects, aged 67 to 93 years in the Age, Gene/Environment Susceptibility Study&#8722;Reykjavik (AGES&#8722;Reykjavik I) in Reykjavik, Iceland from 2001 through 2006. D6 In the present AGES[unreadable]Reykjavik II, NIA and co-sponsoring ICs (NIDCD, NEI, and NINDS) are funding longitudinal follow-up exams. With NIDCD funding, questions will be asked about use of hearing aids, subjective evaluation of hearing acuity including the Gallaudet scale, tinnitus (frequency and duration), ear diseases and operations, and other factors related to hearing. Questions will also be asked about specific dizziness/balance and falling problems that study participants have experienced (since AGES I) or are experiencing currently. In order to examine broad genetic effects, first-degree relatives will be identified in the existing AGES data (i.e., siblings and parent-child combinations). Second-degree relatives or more distant cousins will also be identified. Further investigation of the genetics of hearing loss will be accomplished through participation in a broad genome scan for associations with defined phenotypes, including age-related hearing loss defined on the basis of results in AGES I.